President Donald Trump issued an executive order on Thursday evening barring transactions with ByteDance, forcing the Chinese tech firm to divest itself of its U.S. TikTok operations. 

The order, which is scheduled to go into effect in 45 days, gives a strict timeline for ByteDance to sell the business. Microsoft said on Sunday that it was in conversations with the company about acquiring TikTok’s operations in the U.S., Canada, Australia and New Zealand. 

TikTok, which has more than 100 million users in the U.S., has drawn scrutiny because of its Chinese owner. The Trump administration has worried that, through ByteDance, the personal data of U.S. TikTok users could find its way into the hands of the Chinese government. TikTok has said it does not store U.S. user data in China. 

“These risks are real,” reads Trump’s order, which cites the International Emergency Economic Powers Act as its basis. “The United States must take aggressive action against the owners of TikTok to protect our national security.”

Trump said on July 31 that he was planning to ban TikTok in the U.S. After he spoke with Microsoft CEO Satya Nadella over the weekend, he softened his stance slightly, saying he’d give ByteDance until Sept. 15 to sell the business. 

In the lengthy statement that it issued, Microsoft acknowledged Trump’s concerns and said it would “build on the experience TikTok users currently love, while adding world-class security, privacy, and digital safety protections.” Among the measures it outlined were places to transfer and store all data on American TikTok users to the U.S. and to delete any data that is being backed up on servers outside the country. 

TikTok, meanwhile, has maintained that it doesn’t plan to exit the U.S., which was the second largest market for the app outside India until it was banned in that country in late June. In a TikTok posted over the weekend, Vanessa Pappas, general manager of TikTok’s North American business, highlighted the company’s 1,500 U.S. employees and support from its creator community. “We’re not planning on going anywhere,” she said.

Trump has issued a similar order banning transactions with Tencent and its WeChat messaging service. The executive order, which is also set to go into effect in 45 days, refers to app’s operations in the U.S. as a “national emergency.”